Arduino Nano - Touch Sensor - LED
This tutorial instructs you how to use the Arduino Nano and touch sensor to control the LED. We will learn two different applications:
Application 1 - The LED state is synchronized with the touch sensor state. In detail:
- Arduino Nano turns on the LED when the touch sensor is being touched.
- Arduino Nano turns off the LED when the touch sensor is NOT being touched.
Application 2 - The LED state is toggled each time the touch sensor is touched. More specifically:
- If Arduino Nano detects that the touch sensor has been touched (changing from a HIGH state to a LOW state), it will turn ON the LED if it's currently OFF, or turn OFF the LED if it's currently ON.
- Releasing the touch sensor does not affect to the LED state.
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you. We appreciate your support.
Overview of LED and Touch Sensor
If you are unfamiliar with LED and touch sensor (including pinout, operation, and programming), the following tutorials can help:
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
Application 1 - The LED state is in sync with the touch sensor state
Arduino Nano Code
/*
* This Arduino Nano code was developed by newbiely.com
*
* This Arduino Nano code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/arduino-nano/arduino-nano-touch-sensor-led
*/
#define TOUCH_SENSOR_PIN 11 // The Arduino Nano pin connected to the touch sensor
#define LED_PIN 5 // The Arduino Nano pin connected to the LED
void setup() {
Serial.begin(9600); // Initialize the Serial to communicate with the Serial Monitor.
pinMode(TOUCH_SENSOR_PIN, INPUT); // set arduino pin to input mode
pinMode(LED_PIN, OUTPUT); // set arduino pin to output mode
}
void loop() {
int touch_state = digitalRead(TOUCH_SENSOR_PIN); // read new state
if (touch_state == HIGH) {
Serial.println("The sensor is being touched");;
digitalWrite(LED_PIN, HIGH); // turn on
}
else if (touch_state == LOW) {
Serial.println("The sensor is untouched");
digitalWrite(LED_PIN, LOW); // turn off
}
}
Detailed Instructions
- Connect an Arduino Nano to your computer with a USB cable.
- Launch the Arduino IDE, and select the correct board and port.
- Copy the code and open it in the Arduino IDE.
- Click the Upload button on the Arduino IDE to compile and upload the code to the Arduino Nano.
- Touch the touch sensor and hold it for a few seconds.
- Check out the change in the LED's condition.
You will see that the LED state is in sync with the touch sensor state.
Code Explanation
Check out the line-by-line explanation contained in the comments of the source code!
Application 2 - Touch Sensor toggles LED
Arduino Nano Code - Touch Sensor Toggles LED
/*
* This Arduino Nano code was developed by newbiely.com
*
* This Arduino Nano code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/arduino-nano/arduino-nano-touch-sensor-led
*/
#define TOUCH_SENSOR_PIN 11 // The Arduino Nano pin connected to the touch sensor
#define LED_PIN 5 // The Arduino Nano pin connected to the LED
int led_state = LOW; // The current state of LED
int prev_touch_state; // The previous state of touch sensor
int touch_state; // The current state of touch sensor
void setup() {
Serial.begin(9600); // Initialize the Serial to communicate with the Serial Monitor.
pinMode(TOUCH_SENSOR_PIN, INPUT); // set arduino pin to input mode
pinMode(LED_PIN, OUTPUT); // set arduino pin to output mode
touch_state = digitalRead(TOUCH_SENSOR_PIN);
}
void loop() {
prev_touch_state = touch_state; // save the last state
touch_state = digitalRead(TOUCH_SENSOR_PIN); // read new state
if (prev_touch_state == LOW && touch_state == HIGH) {
Serial.println("The sensor is touched");
// toggle state of LED
led_state = !led_state;
// control LED according to the toggled state
digitalWrite(LED_PIN, led_state);
}
}
Code Explanation
You can locate the explanation in the comment lines of the Arduino Nano code above.
In the code, the expression led_state = !led_state is equal to the following code:
if(led_state == LOW)
led_state = HIGH;
else
led_state = LOW;
Detailed Instructions
- Copy the code and open it in the Arduino IDE.
- Upload the code to the Arduino Nano.
- Touch and release the touch sensor several times.
- Check out the change in the LED's state.
You will see that the LED state is toggled once each time the touch sensor is touched.